Bug 1347963 - part 0 - use global qualification for GuardObjects.h macros; r=erahm
These macros can be used in cases where the `mozilla` namespace might
not refer to the toplevel `mozilla` namespace that was intended. To
ensure that the macros always refer to the `mozilla` namespace in the
global namespace, use the appropriate qualification.

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- *//* vim: set ts=8 sts=2 et sw=2 tw=80: *//* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. *//* Implementation of macros to ensure correct use of RAII Auto* objects. */#ifndef mozilla_GuardObjects_h#define mozilla_GuardObjects_h#include"mozilla/Assertions.h"#include"mozilla/Move.h"#include"mozilla/Types.h"#ifdef __cplusplus#ifdef DEBUG/** * A custom define is used rather than |mozPoisonValue()| due to cascading * build failures relating to how mfbt is linked on different operating * systems. See bug 1160253. */#define MOZ_POISON uintptr_t(-1)namespacemozilla{namespacedetail{/* * The following classes are designed to cause assertions to detect * inadvertent use of guard objects as temporaries. In other words, * when we have a guard object whose only purpose is its constructor and * destructor (and is never otherwise referenced), the intended use * might be: * * AutoRestore savePainting(mIsPainting); * * but is is easy to accidentally write: * * AutoRestore(mIsPainting); * * which compiles just fine, but runs the destructor well before the * intended time. * * They work by adding (#ifdef DEBUG) an additional parameter to the * guard object's constructor, with a default value, so that users of * the guard object's API do not need to do anything. The default value * of this parameter is a temporary object. C++ (ISO/IEC 14882:1998), * section 12.2 [class.temporary], clauses 4 and 5 seem to assume a * guarantee that temporaries are destroyed in the reverse of their * construction order, but I actually can't find a statement that that * is true in the general case (beyond the two specific cases mentioned * there). However, it seems to be true. * * These classes are intended to be used only via the macros immediately * below them: * * MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER declares (ifdef DEBUG) a member * variable, and should be put where a declaration of a private * member variable would be placed. * MOZ_GUARD_OBJECT_NOTIFIER_PARAM should be placed at the end of the * parameters to each constructor of the guard object; it declares * (ifdef DEBUG) an additional parameter. (But use the *_ONLY_PARAM * variant for constructors that take no other parameters.) * MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL should likewise be used in * the implementation of such constructors when they are not inline. * MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT should be used in * the implementation of such constructors to pass the parameter to * a base class that also uses these macros * MOZ_GUARD_OBJECT_NOTIFIER_INIT is a statement that belongs in each * constructor. It uses the parameter declared by * MOZ_GUARD_OBJECT_NOTIFIER_PARAM. * * For more details, and examples of using these macros, see * https://developer.mozilla.org/en/Using_RAII_classes_in_Mozilla */classGuardObjectNotifier{private:bool*mStatementDone;public:GuardObjectNotifier():mStatementDone(reinterpret_cast<bool*>(MOZ_POISON)){}~GuardObjectNotifier(){// Assert that the GuardObjectNotifier has been properly initialized by// using the |MOZ_GUARD_OBJECT_NOTIFIER_INIT| macro. A poison value is// used rather than a null check to appease static analyzers that were// (incorrectly) detecting null pointer dereferences.MOZ_ASSERT(mStatementDone!=reinterpret_cast<bool*>(MOZ_POISON));*mStatementDone=true;}voidsetStatementDone(bool*aStatementIsDone){mStatementDone=aStatementIsDone;}};classGuardObjectNotificationReceiver{private:boolmStatementDone;public:GuardObjectNotificationReceiver():mStatementDone(false){}~GuardObjectNotificationReceiver(){/* * Assert that the guard object was not used as a temporary. (Note that * this assert might also fire if init is not called because the guard * object's implementation is not using the above macros correctly.) */MOZ_ASSERT(mStatementDone);}voidinit(GuardObjectNotifier&aNotifier){aNotifier.setStatementDone(&mStatementDone);}};}/* namespace detail */}/* namespace mozilla */#undef MOZ_POISON#endif /* DEBUG */#ifdef DEBUG# define MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER \ ::mozilla::detail::GuardObjectNotificationReceiver _mCheckNotUsedAsTemporary;# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM \ , ::mozilla::detail::GuardObjectNotifier&& _notifier = \ ::mozilla::detail::GuardObjectNotifier()# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM \ ::mozilla::detail::GuardObjectNotifier&& _notifier = \ ::mozilla::detail::GuardObjectNotifier()# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL \ , ::mozilla::detail::GuardObjectNotifier&& _notifier# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL \ ::mozilla::detail::GuardObjectNotifier&& _notifier# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT \ , ::mozilla::Move(_notifier)# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_TO_PARENT \ ::mozilla::Move(_notifier)# define MOZ_GUARD_OBJECT_NOTIFIER_INIT \ do { _mCheckNotUsedAsTemporary.init(_notifier); } while (0)#else# define MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_IN_IMPL# define MOZ_GUARD_OBJECT_NOTIFIER_ONLY_PARAM_TO_PARENT# define MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT# define MOZ_GUARD_OBJECT_NOTIFIER_INIT do { } while (0)#endif#endif /* __cplusplus */#endif /* mozilla_GuardObjects_h */